1. Field of the Invention
The present invention relates to hand-held tools, such as a hand-held disk grinder.
2. Description of the Related Art
A known hand-held disk grinder has a tool body that has an electric motor disposed therein and serves also as a grip portion for being grasped by an operator. A gear head is assembled with a front portion of the tool body and is coupled to a spindle, to which a circular grinding wheel (i.e., an end tool) is mounted. The gear head has a bevel gear disposed therein. An axis of the spindle or the rotational axis of the grinding wheel extends perpendicular to a motor axis of the motor.
In general, the disk grinder has a grinding wheel cover that surrounds the grinding wheel for preventing ground powder or the like produced during a grinding operation from scattering toward the side of the operator. The grinding wheel cover includes a substantially semi-circular cover body surrounding the grinding wheel and an annular cover mounting portion secured to a bearing box in such a manner that it is wound around the bearing box. The bearing box may be positioned at the lower portion of the gear head and has a bearing disposed therein for rotatably supporting the spindle.
Because the disk grinder is grasped while it is oriented in various directions according to different modes of operation, the grinding wheel cover is configured such that it can be moved to a desired position around the grinding wheel (i.e., about the spindle axis) according to the orientation of the grinding wheel cover. In order to change the position of the grinding wheel cover, for example, a fixing screw tightening type structure is incorporated. According to this type of structure, a fixing screw of the cover mounting portion is loosened, the grinding wheel cover is moved to a desired position, and the cover mounting portion is then fixed in position by tightening the fixing screw. However, because this type of structure requires a tool, such as a screwdriver, the position changing operation is troublesome. Therefore, there has been proposed a tool-less type structure that enables the position of the grinding wheel cover to be changed and fixed at one-touch without need of a tool. Techniques relating to a tool-less type structure for changing a position of a grinding wheel cover are disclosed in U.S. Pat. No. 4,924,635 (also published as Japanese Patent Publication No. 5-79466) and U.S. Pat. No. 5,386,667 (also published as Japanese Patent No. 3447287). With these techniques, it is possible to improve the operability of the grinding wheel, enabling to quickly perform the girding operation.
However, according the techniques disclosed in the above U.S. patents, an operation member for locking and unlocking the position of the grinding wheel cover is positioned at or in the vicinity of the grinding wheel cover support portion, and therefore, it is difficult for the operator to view the operation member.
Therefore, there is a need in the art for a hand-held tool that is further improved in its operability.